SpringBoot学习笔记：Json数据的处理

Posted 2022-12-08 听风者-better

1.SpringBoot默认对Json的处理

Springboot默认使用jackson对数据进行处理，我们先看下默认的处理方式

1.1 创建User实体类

public class User 
    private int id;
    private String username;
    private String password;
    private Date birthday;
    //省略set/get和带参构造方法

1.2 创建Controller类

@RestController
@RequestMapping(value = "/user")
public class UserController 

    @GetMapping(value = "/one")
    public User getUser() 
        User user = new User(1, "唐万言", "123456", new Date());
        return user;
    

    @GetMapping(value = "/list")
    public List<User> getUserList() 
        User u1 = new User(1, "唐万言", "123456", new Date());
        User u2 = new User(2, "王心心", null, new Date());
        List<User> list = new ArrayList<>();
        list.add(u1);
        list.add(u2);
        return list;
    

1.3 测试返回结果

请求：http://localhost:8080/user/one

    "id": 1,
    "username": "唐万言",
    "password": "123456",
    "birthday": "2020-05-10T15:06:18.767+0000"

请求：http://localhost:8080/user/list

[
    
        "id": 1,
        "username": "唐万言",
        "password": "123456",
        "birthday": "2020-05-10T15:06:47.825+0000"
    ,
    
        "id": 2,
        "username": "王心心",
        "password": null,
        "birthday": "2020-05-10T15:06:47.825+0000"
    
]

1.4 自定义json的格式化配置

从返回值可以看出返回值都可以转成相应的 json 格式，但是格式都是默认，我们可以自己写一个配置类修改返回的格式

@Configuration
public class JsonConfig 

    @Bean
    ObjectMapper objectMapper()
        ObjectMapper objectMapper = new ObjectMapper();
        //格式化日期
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy/MM/dd"));
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() 
            @Override
            public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException 
                jsonGenerator.writeString("");
            
        );
        return objectMapper;
    

返回json格式

[
    
        "id": 1,
        "username": "唐万言",
        "password": "123456",
        "birthday": "2020/05/10"
    ,
    
        "id": 2,
        "username": "王心心",
        "password": "",
        "birthday": "2020/05/10"
    
]

2.使用FastJson的设置

2.1 引入依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.35</version>
</dependency>

2.2 添加配置

fastjson需要添加配置，不然json还是用默认的jackson处理

@Configuration
public class JsonConfig 

    @Bean
    FastJsonHttpMessageConverter fastJsonHttpMessageConverter()
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        FastJsonConfig config = new FastJsonConfig();
        converter.setFastJsonConfig(config);
        config.setDateFormat("yyyy/MM/dd");
        config.setSerializerFeatures(SerializerFeature.WriteNullStringAsEmpty);
        converter.setDefaultCharset(Charset.forName("UTF-8"));
        //解决中文乱码问题
        List<MediaType> mediaTypes = new ArrayList<>();
        mediaTypes.add(MediaType.APPLICATION_JSON);
        converter.setSupportedMediaTypes(mediaTypes);
        return converter;
    

3.同一返回Json格式数据

3.1 创建统一json格式类

public class BaseResult<T> 
    private String code;
    private String message;
    private T data;

    /**
     * 无数据返回,操作成功
     */
    public BaseResult() 
        this.code = "0";
        this.message = "操作成功";
    

    /**
     * 没有数据返回,自定义状态码和提示信息
     *
     * @param code
     * @param message
     */
    public BaseResult(String code, String message) 
        this.code = code;
        this.message = message;
    

    /**
     * 有数据返回时，操作成功
     *
     * @param data
     */
    public BaseResult(T data) 
        this.code = "0";
        this.message = "操作成功";
        this.data = data;
    

    /**
     * 有数据返回时，状态码为0,自定义提示信息
     *
     * @param message
     * @param data
     */
    public BaseResult(T data, String message) 
        this.code = "0";
        this.message = message;
        this.data = data;
    

    //省略set/get方法

3.2 修改Controller返回结果

@RestController
@RequestMapping(value = "/user")
public class UserController 

    @GetMapping(value = "/one")
    public BaseResult<User> getUser() 
        User user = new User(1, "唐万言", "123456", new Date());
        return new BaseResult<>(user);
    

    @GetMapping(value = "/list")
    public BaseResult<List> getUserList() 
        User u1 = new User(1, "唐万言", "123456", new Date());
        User u2 = new User(2, "王心心", null, new Date());
        List<User> list = new ArrayList<>();
        list.add(u1);
        list.add(u2);
        return new BaseResult<>(list,"数据集获取成功");
    

3.3 请求返回结果

请求：http://localhost:8080/user/one

    "code": "0",
    "data": 
        "birthday": "2020/05/10",
        "id": 1,
        "password": "123456",
        "username": "唐万言"
    ,
    "message": "操作成功"

请求：http://localhost:8080/user/list

    "code": "0",
    "data": [
        
            "birthday": "2020/05/10",
            "id": 1,
            "password": "123456",
            "username": "唐万言"
        ,
        
            "birthday": "2020/05/10",
            "id": 2,
            "password": "",
            "username": "王心心"
        
    ],
    "message": "数据集获取成功"